Method of making an asphalt composition containing ester bottoms

ABSTRACT

This invention involves the addition of ester bottoms to an asphalt paving composition to improve the usable temperature range (UTR). The ester bottoms are a byproduct of refining a feedstock containing all or a portion of vegetable oil or animal fat.

CROSS REFERENCE TO RELATED APPLICATION

The present patent application is based upon and claims the benefit ofprovisional patent application No. 62/341,700, filed on May 26, 2016.

FIELD OF THE INVENTION

The invention relates to asphalt compositions and the process for theimprovement of their properties. The invention further relates to amodified asphalt composition useful for a variety of applications,particularly paving asphalt and for construction materials utilizingsuch compositions.

BACKGROUND OF THE INVENTION

The invention relates to an asphalt paving composition made with esterbottoms. The Environmental Protection Agency provides a discussion ofasphalt roads at http://www.epa.gov/ttn/chief/ap42/cho4/final/c4s05.pdfwhich is incorporated herein by reference.

Ester bottoms are a low value by-product of vegetable oil or animal fatrefining to produce methyl ester. There is little known value for esterbottoms and they are currently marketed for animal feed, lubricants, orother industrial uses at a low price point.

Asphalt materials are used in a wide variety of applications includingbut not limited to paving asphalt and asphalt shingles. Paving asphaltmust be sufficiently durable to withstand high and low temperatureextremes without undue wear, cracking or melting. Paving asphalt hardenswhile in service (age hardening). Age hardening is caused by an increasein viscosity of the asphalt mixture and the gradual loss of flexibility.The degree and the rate of the hardening of the paving asphaltcomposition or cement are factors affecting the durability of an appliedsurface. It is believed that the reaction of the asphalt compositionwith atmospheric oxygen is the principle cause of asphalt hardening inpavement. Therefore, the asphalt industry has long sought to reduce agehardening.

Some conventional refined asphalts have been found to be incapable ofreacting some requirements for resistance to either low temperaturethermal cracking or high temperature rutting resistance in certainclimates. Modifiers such as elastomers, plasterers, chemical gellants,and chemical modifiers can be effective in improving either, orsometimes both, low temperature thermal cracking or high temperaturerutting resistance. These modifiers have varying levels of effectivenessand cost.

Conventional practice to improve low temperature properties adds softerasphaltic compounds, aromatic oils, or other additives to soften orplasticize the asphalt composition. In order to reach acceptable lowtemperature properties, excessive amounts of soft asphaltic materials orfluxes may be required

In addition, aromatic oils used in combination with polymers can improvethe rutting resistance of asphalt. However, many times, the level ofpolymer required to reach the desired level of rutting resistancebecomes undesirable as a result of excessive cost, rendering thecomposition not feasible for use as a paving composition.

Asphalt compositions may be derived, as indicated from any well-knownbituminous or asphaltic substance obtained from natural sources orderived from a number of sources such as, shale oil, coal tar, and thelike as well as the mixtures of two or more of such materials. Asindicated, paving grade asphalt compositions are preferred in thepresent invention. Such paving asphalt compositions are often referredto as viscosity, penetration graded, or performance graded (PG) asphaltshaving penetration up to 400 as measured by ASTM method D5.

As a result of the 1987 Intermodal Surface Transportation Efficiency Act(ISTEA), a $150 million research study was commissioned in which $50million was spent towards asphalt research for improving asphaltpavements. As a product of that research which was concluded in 1992,the Strategic Highway Research Program (SHRP) produced what is now knownas the Superpave Performance Graded Binder Specification in whichasphaltic binders are graded or characterized according to theirrelative performance in resistance to rutting, shoving or deformation athigh temperatures, fatigue at intermediate temperatures, and thermalcracking resistance at low temperatures. Asphalts which normally wouldbe graded either under the penetration or viscosity specifications arenow graded as PG (Performance Graded) binders. As such, theirdesignation will be representative of their resistance at both high andlow temperature, indicating their useable temperature range (UTR) as aPG AA-BB where AA=high temperature resistance in degrees Celsius and BBis low temperature cracking resistance in minus degrees Celsius, i.e.,PG 64-22 would prevent rutting up to 64° C. (147° F.) and lowtemperature cracking to a minus 22° C. (−72° F.). Preferred asphalts arethe performance graded asphalts such as PG 46-40; PG 48-34; PG 46-28, PG52-40; PG 52-34; PG 52-28; PG 52-22, PG 58-40, PG 58-34, PG 58-28, PG PG58-22, PG 64-40, PG 64-34, PG64-28, PG 64-22, PG 70-40, PG 70-34, PG70-28, PG 70-22, PG 76-40, PG 76-34, PG 76-28, PG 76-22, PG 82-34, PG82-28, or PG 82-22. The PG in the title referring to Performance Graded,the first numeric designation referring to the binders high temperaturerutting or deformation resistance temperature range limit. The lastnumeric designation references the cracking resistance temperature limitof the binder.

Areas of high loading or slow or standing traffic as well as areas wheretemperature extremes can be experienced in excess of 86° C. (187° F.)between high and low temperature levels will require the use ofmodifiers to obtain the increased useful temperature range. As a result,it has been common to start with softer asphalts to reach lowtemperature properties, while adding modifiers such as polymers toachieve high temperature rutting resistance. The use of aromatic oilsalso aids low temperature properties. As such, extensive levels ofpolymer addition is required to regain high temperature properties,especially when using aromatic oils. The use of aromatic oils cansolvate the polymer to a higher degree and thus require a higher levelof polymer to be used to obtain the desired high temperature ruttingresistance.

A common practice of softening asphalts in the industry is to add heavyvacuum gas oil (HVGO) to paving asphalt to reach the desired useabletemperature range (UTR). HVGO may be added after refining or, in someapplications, it is not refined out of the asphalt materials. HVGO is avaluable commodity currently selling at about $150/ton premium over theprice of asphalt, depending on the market. Therefore, adding HVGO toasphalt is an undesirable fix as it increases the cost of pavingasphalt.

Notwithstanding the considerable efforts previously expended to providean improved asphalt paving composition, there remains a continued needto increase the useable temperature range and reduce the cost associatedwith manufacturing asphalt paving materials. The present inventionaddresses both of these needs.

SUMMARY OF THE INVENTION

In producing methyl esters, including biodiesel, a feed-stock containingall or a portion of vegetable oil or animal fats is reacted and refinedto produce finished products. As a part of this process, a number ofby-products are produced, having varying degrees of value. On the lowend of the value spectrum are ester bottoms. Ester bottoms are aco-product of refining methyl ester, including biodiesel, that is notglycerin or skimmed fatty acids. Ester bottoms generally contain methylesters, monoglycerides, diglycerides, triglycerides, sodium soapsproduced from the addition of sodium methoxide (catalyst), andunsaponafiables. The unsaponafiables generally make up about 10% of theester bottoms. Ester bottoms, as used in the preferred embodiment ofthis invention, have a viscosity range 10-900 cP at 64 degrees Celsius.

In the preferred embodiment, the invention involves the addition ofester bottoms to an asphalt paving composition to improve the useabletemperature range (UTR). Very specifically, the ester bottoms affect thelow temperature properties more significantly than the high temperatureproperties. Generally, the modified asphalt composition will comprise(a) about 0.1% to about 50% of ester bottoms, (b) about 0 to about 20%of a polymer modifier, (c) 50 to about 99.9% of an asphalt obtained fromconventional vacuum distillation, solvent refining or naturallyoccurring mineral sources.

Refiners, or user producers, will often add a polymer to paving asphaltto increase the high temperature property of the paving asphalt forwarmer climates. The ester bottom modified asphalt paving compositionincreases the useful temperature range. Therefore the amount of polymeradditive required to reach a desirable higher temperature range can bereduced, thus reducing the cost of manufacturing pavement asphalt.

Another advantage of the invention is the amount of ester bottoms usedto produce a desired finished product is less than the amount of HVGO(heavy vacuum gas oil), or other modifiers currently available, requiredto produce an equivalent amount of finished product.

A typical paving asphalt mixture comprises a mixture of components.Principal ingredients of the paving asphalt mixture are an asphaltcomposition or cement and aggregate or aggregate material. In suchmixtures, the ratio of asphalt composition to aggregate material varies,for example, according to the aggregate material type and the nature ofthe asphalt composition. As used herein, the terms “asphaltcomposition”, “asphalt cement” or “asphalt binder” are understood torefer to any of a variety of organic materials, solid or semi-solid atroom temperature, which gradually liquefy when heated, and in which thepredominate constituents are naturally occurring bitumen, e.g., TrinidadLake, or residues commonly obtained in petroleum, synthetic petroleum,or shale oil refining, or from coal tar or the like. For example, vacuumtower bottoms produced during the refining of conventional or syntheticpetroleum oils is a common residue material useful as an asphaltcomposition. A “paving asphalt composition”, “paving asphalt cement”, or“paving asphalt binder”, accordingly is an asphalt composition orasphalt cement having characteristics which dispose the composition touse as a paving material. This is contrasted, for example, with anasphalt composition suited for use as a roofing material. “Roofingasphalts”, usually have a higher softening point, and are thus moreresistant to flow from heat on roofs. The higher softening point isgenerally imparted by the air blowing processes by which they arecommonly produced. Paving asphalt mixtures may be formed and applied ina variety of ways, as well understood by those skilled in the art. Forexample, the paving asphalt composition and the aggregate can be mixedand applied at elevated temperatures while in the fluid state to formthe pavement or road surface. See particularly U.S. patent applicationSer. No. 5,580,376 to Hayner.

Some examples of polymers used for modifying asphalts include: StyreneButadiene (SB), ethylene-vinyl-acetate, ethylene-methyl-acrylate,ethylene butyl acrylate, poly-propylene, atactic polypropylene,polystyrene, polyethylene, LDPE, HDPE, oxidized high densitypoly-propylene, poly-phosphoric acid (PPA), natural rubber,polybutadiene, epoxy resins, polyurethane resins, acrylic resins,phenolic resins, gilsonite, lignin, diblock polymers,Styrene-Butadiene-Styrene (SBS), triblock polymers which may be eitherlinear or radial, styrene-isoprene-styrene (SIS), diblocked polymers,hydrotreated SBS, Styrene Ethylene Butadiene Styrene polymers (SEBS),Styrene Butadiene Rubber (SBR), polyacrylamide, e.g., those described inU.S. Pat. No. 4,393,155; Glycidyl-containing ethylene copolymers in U.S.Pat. No. 5,331,028; or Crum Rubbers.

Asphalt is the most recycled material in the world. Milled road surfacesare reused. Many new roads are composed of 20% recycled asphalt and ashigh as 60% in some applications. The reclaimed asphalt is highlyoxidized from years of use, and can be rejuvenated. There arerejuvenators currently on the market at a high price point. Anotheradvantage of the invention is the ester bottoms can be used as arejuvenator for recycled asphalt.

The ester bottom modified asphalt may have many desirable applicationsincluding but not limited to paving asphalt, asphalt emulsions, cutbackasphalts, and roofing flux.

Other objects and advantages of the present invention will becomeapparent to those skilled in the art upon a review of the followingdetailed description of the preferred embodiments and the accompanyingdrawings.

IN THE DRAWINGS

FIG. 1 is a schematic flow diagram for bio-refining.

FIG. 2 is a plot of ester bottoms vs. HVGO in asphalt.

FIG. 3 is a plot of ester bottoms PG temperatures for a number ofdifferent asphalt compositions.

FIG. 4 is a table of test results on a number of different asphaltcompositions when mixed with various amounts of ester bottoms.

FIG. 5 is a table of test results on a number of different asphaltcompositions when mixed with various amounts of ester bottoms.

FIG. 6 is a plot of results of tensile tests comparing an ester bottommodified asphalt with three polymer modified asphalts.

FIG. 7 is a plot of results of a rutting resistance test of an esterbottom modified asphalt with three polymer modified asphalts.

FIG. 8 is a plot of results of a compaction tension test comparing anester bottom modified asphalt with two polymer modified asphalts.

FIG. 9 is a plot of a Semi Circular Bend test comparing an ester bottommodified asphalt with two polymer modified asphalts.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 feedstock is brought from the storage tanks to thedryer (T2101) wherein moisture is removed. This dry oil is then fed intoa three-stage continuous reactor/settler system (T2102) where methoxidecatalyst and methanol are added to each stage. Methanol reacts with thedry oil to produce methyl ester and glycerin. The dry oil is reacted toless than 1% monoglyceride and virtually no diglycerides ortriglycerides as it leaves the last settler. Glycerin settles out of theof the reaction mixture and is directed from the reactors downstream forfurther refining. The ester phase is what remains after the glycerin isremoved. The ester phase is then transferred to a single stage flashdistillation tank (V-2107) to remove any remaining methanol. The esterphase is then water washed (T2103) to remove glycerin, soap, methanol,and methoxide catalyst. The washed methyl esters are dried under vacuum(T2104) to remove more methanol and water. Sodium methoxide is added tothe dryer to back react any glycerin and monoglycerides intodiglycerides and triglycerides. The methyl esters leave the ester dryerand are preheated before entering an ester surge tank (S2201). Themethyl esters from the ester surge tank are then distilled to separatethe purified methyl esters from the ester bottoms. The ester bottoms aretransferred from the distillation tower (T2211) to an ester bottom surgetank (S2202) while the purified methyl ester is transferred from thedistillation tower to a storage tank for distribution or sale.

The ester bottoms produced in methyl ester refining are added to anysuitable asphalt composition or cement, for example, industrial asphaltsused for coatings, sealants, roofing materials, adhesives, and otherapplications. However, paving grade asphalts are used in the preferredembodiment of the invention. The asphalt feed composition will determinethe amount of ester bottoms required.

Referring now to FIG. 2 , there is illustrated a comparison of heavyvacuum gas oil modified asphalt compared with ester bottoms modifiedasphalt. It can be seen in FIG. 2 that, at similar points, the esterbottoms modified asphalt produces a PG73-23 (UTR=96) versus a HVGOPG71-23 (UTR=94). Similarly, the higher the quantity of modifiers in theasphalt, the ester bottoms produce PG66-29 (UTR=95) versus an HVGOPG63-29 (UTR=92). The ester bottoms modified asphalt presents animproved UTR when compared with HVGO modified asphalts.

The type of asphalt used for the present invention can vary asillustrated by FIGS. 3 and 4 . The asphalts may include solventdeasphalting bottoms (SDA). FIGS. 3 and 4 illustrate testing which wasdone on a PG64-22 (Sample A), PG64-22 (Sample B), and two SDA blends(Samples C and D), and two stiff vacuum tower bottoms blends (Samples Eand F). For instance, asphalt from two different refineries (SamplesA&B), mixed with 3% ester bottoms resulted in different end products.Similarly, ester bottoms added to SDA or coker feeds affect the finishedproducts differently. Therefore, the weight percentage of ester bottomsrequired for blending is determined by the asphalt composition.

EXAMPLE 1

Referring now to FIG. 4 a conventional PG 64-22 (Sample A) is used. Thecontrol sample at high temperature is approximately 65° C., and the lowtemperature compliance is actually −25° C. Ester bottoms are added tothe Sample A and the resulting product has a high temperature complianceof 60.1° C. and a low temperature compliance of −29.6° C. The useabletemperature range of the control equals 86° C. whereas the estermodified composition has a useable temperature range of 89.7° C.

EXAMPLE 2

Referring to FIG. 4 , Sample B PG 64-22 has an initial high temperaturecontrol of 67.7° C. and the low temperature control is −24.6° C.resulting in a UTR of 92.3. After the addition of 3% ester bottoms thehigh temperature compliance is 62.4° C. and the low temperaturecompliance is −29.9° C. resulting in a useable temperature range of93.2° C., while lowering the lower temperature compliance significantly.

EXAMPLE 3

Referring again to FIG. 4 , Samples C & D, SOA blends, were tested.Sample C having a high temperature compliance of 67.7° C. and a lowtemperature compliance of −18° C. Ester bottoms were added in the amountof 2.25% and 5.77%. The 2.25% ester bottoms addition resulted in a UTRof 87.8° C., while the 5.77% ester bottoms addition resulted in a UTR89° C. In the Sample D test the 3.70% ester bottoms addition resulted inan 89.8° C. UTR and a 7.1% ester bottoms addition resulted in an 88.8°C. UTR.

It can be seen from FIGS. 2-4 that ester bottoms modified asphalts areat least as good as, if not better at maintaining a UTR than the moreexpensive HVGO and SDA modified asphalts.

Referring now to FIG. 5 , tensile strength testing was employed againstthree SDA modified binders (1, 2, 3) in comparison with an ester bottomsmodified binder (4). Moisture sensitivity results for the three SDAmodified PG64-22 asphalts and the ester bottoms modified blend show thatthe ester bottoms modified blend competed very well against binders 1, 2and 3. Both dry and wet strains are very strong. During this test adisk-shaped sample of the binder is pulled apart to measure the crackinitiation and propagation. By measuring the area under the load and thedisplacement curve, fracture energy is calculated for the sample. Thistest provides an understanding of a mixture's ability to resist crackingat both low and intermediate temperatures.

Referring now to FIG. 6 the results of a rutting resistance test, knownas the Hamburg Wheel Test, compares binders 1, 2 and 3 against estermodified binder 4. Again, the ester modified binder 4 performs favorablywhen compared to the other refinery produced PG64-22. The test isperformed by repeatedly tracking a loaded wheel over samples in heatedbath water. The deformation of the samples versus the number of passesis observed. The Hamburg Wheel Test is used to measure both rutting andstripping risks.

Referring now to FIG. 7 the results of a Disk Shaped Compaction Tensiontest (DCT) are shown. The DCT is a measure of low temperature andreflective cracking. Binder 4 with the ester bottoms additive wascompared against binders 2 and 3. Binder 4 again provided results equaland favorable to the refinery binders. During this test, one set ofsamples is tested as it exists. For this test, two sets of each binderare tested. One set of the mixed binders are tested as is under dryconditions. The second set of test binders is put through a freeze/fallcycle and is then conditioned in water. The strength for each mix ismeasured from the load required to crack the sample. The reported numberof this graph is the strength ratio of the wet versus dry condition.This strength ratio provides information regarding the moisturesusceptibility of the asphalt mix.

FIG. 8 provides the results of a Semi Circular Bend test against binder2, binder 3 and binder 4 with ester bottoms. This test provides anindicator of resistance to crack propagation and predicts fractureperformance. The test shows that binder 4 with ester bottoms additiveperformed better than binders 2 and 3. The test is performed by 3 pointbending of a semi-circular shaped specimen with an introduced notch.This induces tension at the bottom of the sample, resulting in crackpropagation throughout the specimen. The energy required to fracture thesample is calculated. The test is run at normal temperatures.

The above detailed description of the present invention is given forexplanatory purposes. It will be apparent to those skilled in the artthat numerous changes and modifications can be made without departingfrom the scope of the invention. Accordingly, the whole of the foregoingdescription is to be construed in an illustrative and not a limitativesense, the scope of the invention being defined solely by the appendedclaims.

We claim:
 1. A method of making paving a modified asphalt compositioncomprising: adding 0.1 wt % to 20 50 wt % ester bottoms to an asphaltmixture wherein the ester bottoms are a byproduct of methyl esterrefining; and adding 0-20 wt % of a polymer modifier to the esterbottoms and asphalt mixture.
 2. The method according to of claim 1,wherein the ester bottoms contain one or more of methyl esters, sodiumsoap, monoglycerides, diglycerides, triglycerides, and orunsaponifiables.
 3. The method according to of claim 2, wherein theunsaponifiables make up about 10 wt % of the ester bottoms.
 4. Themethod of claim 1, wherein the ester bottoms have a viscosity range of10-900 cp cP at 64° C.
 5. A method of making a paving modified asphaltcomposition comprising adding ester bottoms to an asphalt mixture toincrease the useable temperature range of the paving asphalt, whereinthe ester bottoms are a byproduct of methyl ester refining.
 6. A methodof making a paving modified asphalt composition comprising adding esterbottoms to an asphalt mixture to meet a predetermined useabletemperature range, wherein the ester bottoms are a byproduct of methylester refining.
 7. A method of making a modified asphalt composition,the method comprising: reacting methanol and dry oil to generatereaction products, the reaction products including at least methyl esterand glycerin, the dry oil being an oil that is at least partially driedto remove moisture therefrom; settling the glycerin from the reactionproducts; creating a distillation feedstock that has at least a portionof the glycerin removed from the reaction products; distilling thedistillation feedstock; recovering distillation bottoms as esterbottoms; and adding the ester bottoms and an asphalt-modifying polymerto an asphalt to define a modified asphalt composition, the esterbottoms being between about 0.1 wt % to about 50 wt % of the modifiedasphalt composition, the asphalt-modifying polymer being between about 0wt % to about 20 wt % of the modified asphalt composition, and theasphalt being between about 50 wt % to about 99.9 wt % of the modifiedasphalt composition.
 8. The method of claim 7, wherein the reacting ofthe methanol and the dry oil includes reacting the methanol and the dryoil in a multistage continuous reactor and adding methoxide catalyst toone or more stages of the multistage continuous reactor.
 9. The methodof claim 7, wherein the ester bottoms are added to the asphalt in anamount to achieve a preselected useable temperature range of themodified asphalt composition.
 10. The method of claim 7, wherein theester bottoms include unsaponifiables in an amount of at least about 10%thereof.
 11. The method of claim 7, wherein the ester bottoms have aviscosity range of between about 10 cP and about 900 cP at 64° C. 12.The method of claim 7, wherein the ester bottoms include diglyceridesand triglycerides.
 13. The method of claim 7, wherein the asphaltincludes from about 20 wt % to about 60 wt % recycled asphalt.
 14. Themethod of claim 7, wherein the asphalt-modifying polymer has one or moremonomers selected from the group consisting of butadiene, styrene, vinylacetate, ethylene, propylene, acrylate, isoprene, and acrylamide. 15.The method of claim 7, wherein adding the ester bottoms to the modifiedasphalt composition increases useable temperature range of the modifiedasphalt composition.
 16. The method of claim 7, wherein the dry oil isderived from one or more of a vegetable oil or an animal fat.
 17. Amethod of making a modified asphalt composition, the method comprising:reacting methanol with dry oil containing one or more of a vegetable oilor an animal fat to generate reaction products, the reaction productsincluding at least methyl ester and glycerin; settling the glycerin fromthe reaction products; removing at least a portion of the glycerin fromthe reaction products to leave an ester phase; distilling the esterphase to separate purified methyl esters from ester bottoms; andblending the ester bottoms and an asphalt-modifier with an asphalt todefine a modified asphalt composition, the ester bottoms being betweenabout 0.1 wt % to about 50 wt % of the modified asphalt composition, theasphalt-modifier being between about 0 wt % to about 20 wt % of themodified asphalt composition, and the asphalt being between about 50 wt% to about 99.9 wt % of the modified asphalt composition.
 18. The methodof claim 17, wherein the reading of the methanol and the dry oilincludes reacting the methanol and the dry oil in a multistagecontinuous reactor and adding methoxide catalyst to one or more stagesof the multistage continuous reactor.
 19. The method of claim 17,wherein the ester bottoms include unsaponifiables in an amount of atleast about 10% thereof.
 20. The method of claim 17, wherein the esterbottoms have a viscosity range of between about 10 cP and about 900 cPat 64° C.
 21. The method of claim 17, wherein the asphalt includes fromabout 20 wt % to about 60 wt % recycled asphalt.
 22. A method of makinga modified asphalt composition, the method comprising: reacting methanolwith dry oil containing one or more of a vegetable oil or an animal fatto generate reaction products, the reaction products including at leastmethyl ester and glycerin; settling the glycerin from the reactionproducts; removing at least a portion of the glycerin from the reactionproducts to leave an ester phase; washing the ester phase with water toremove one or more of soap, methanol, catalyst or additional glycerin;drying the washed ester phase to define dried methyl esters; distillingthe dried methyl esters to separate purified methyl esters from esterbottoms; and blending the ester bottoms and an asphalt-modifier with anasphalt to define a modified asphalt composition, the asphalt-modifierbeing selected from the group consisting of a polymer, a resin,polyphosphoric acid, gilsonite, lignin, and crumb rubber.
 23. The methodof claim 22, wherein the modified asphalt composition includes betweenabout 0.1 wt % to about 50 wt % of ester bottoms, between about 0 wt %to about 20 wt % of the asphalt-modifier, and between about 50 wt % toabout 99.9 wt % of the asphalt.
 24. The method of claim 22, wherein theester bottoms include unsaponifiables in an amount of at least about 10%thereof.
 25. The method of claim 22, wherein the ester bottoms have aviscosity range of between about 10 cP and about 900 cP at 64° C. 26.The method of claim 22, wherein the asphalt includes from about 20 wt %to about 60 wt % recycled asphalt.
 27. A method of making a modifiedasphalt composition that rejuvenates recycled asphalt, the methodcomprising: reacting methanol and dry oil to generate reaction products,the reaction products including at least methyl ester and glycerin, thedry oil including one or more of a vegetable oil or an animal fat thathas at least some moisture removed therefrom prior to reaction with themethanol; settling the glycerin from the reaction products; removing atleast a portion of the glycerin from the reaction products to leave anester phase; distilling the ester phase to separate purified methylesters from ester bottoms; and adding the ester bottoms to recycledasphalt to define a modified asphalt composition, the recycled asphaltbeing obtained from a milled road surface, the ester bottoms beingbetween about 0.1 wt % to about 50 wt % of the modified asphaltcomposition and the recycled asphalt being between about 50 wt % toabout 99.9 wt % of the modified asphalt composition.
 28. The method ofclaim 27, further comprising adding an asphalt-modifying polymer to themodified asphalt composition, the asphalt-modifying polymer beingbetween about 0 wt % to about 20 wt % of the modified asphaltcomposition.
 29. The method of claim 28, wherein the asphalt-modifyingpolymer is one or more of styrene butadiene, ethylene-vinyl-acetate,ethylene-methyl-acrylate, ethylene butyl acrylate, poly-propylene,atactic polypropylene, polystyrene, polyethylene, LDPE, HDPE, oxidizedhigh density poly-propylene, poly-phosphoric acid, natural rubber,polybutadiene, epoxy resins, polyurethane resins, acrylic resins,phenolic resins, gilsonite, lignin, diblock polymers,styrene-butadiene-styrene, linear triblock polymers, radial triblockpolymers. styrene-isoprene-styrene, diblocked polymers, hydrotreatedstyrene-butadiene-styrene, styrene ethylene butadiene styrene polymers,styrene butadiene rubber, polyacrylamide, glycidyl-containing ethylenecopolymers, or crumb rubber.
 30. A method of making a modified asphaltcomposition that resists moisture susceptibility, the method comprising:reacting methanol with dry oil to generate reaction products, thereaction products including at least methyl ester and glycerin, the dryoil including one or more of a vegetable oil or an animal fat that hasat least some moisture removed therefrom prior to reaction with themethanol; settling the glycerin from the reaction products; removing atleast a portion of the glycerin from the reaction products to leave anester phase; washing the ester phase with water to remove one or more ofsoap, methanol, catalyst or additional glycerin; drying the washed esterphase to define dried methyl esters; distilling the dried methyl estersto separate purified methyl esters from ester bottoms; and blending theester bottoms and an asphalt to define a modified asphalt compositionthat resists cracking, the ester bottoms being between about 0.1 wt % toabout 50 wt % of the modified asphalt composition and the asphalt beingbetween about 50 wt % to about 99.9 wt % of the modified asphaltcomposition.
 31. The method of claim 30, further comprising adding anasphalt-modifying polymer to the modified asphalt composition, theasphalt-modifying polymer being between about 0 wt % to about 20 wt % ofthe modified asphalt composition.
 32. The method of claim 31, whereinthe asphalt-modifying polymer is selected from the group consisting of apolymer, a resin, polyphosphoric acid, gilsonite, lignin, and crumbrubber.
 33. A method of making a modified asphalt composition, themethod comprising: obtaining a distillation bottoms of a distilledmethyl ester product that results from reaction between methanol and atleast one of vegetable oil or animal fat from which glycerin is settledand removed from the methyl ester product prior to distillation, thedistillation bottoms being defined as ester bottoms; obtaining anasphalt, and blending the ester bottoms and the asphalt to define amodified asphalt composition, the ester bottoms being between about 0.1wt % to about 50 wt % of the modified asphalt composition and theasphalt being between about 50 wt % to about 99.9 wt % of the modifiedasphalt composition.
 34. The method of claim 33, further comprisingblending an asphalt-modifying polymer together with the ester bottomsand the asphalt to define the modified asphalt composition, theasphalt-modifying polymer being between about 0 wt % to about 20 wt % ofthe modified asphalt composition.
 35. The method of claim 34, whereinthe asphalt-modifying polymer is selected from the group consisting of apolymer, a resin, polyphosphoric acid, gilsonite, lignin, and crumbrubber.
 36. The method of claim 33, wherein the asphalt includesrecycled asphalt that is obtained from a milled road surface.